1. Field of the Invention
This invention relates to a method of measuring quickly and accurately the concentration of a combustible component in a liquid or gas phase. More particularly, it is concerned with a method of measuring the concentration of a combustible component accurately in which a gas having a high oxygen content is used as a carrier gas for detection by a semiconductor gas sensor.
2. Description of the Prior Art
A flame ionization detector, a catalyst type detector, a semiconductor gas sensor, etc. are known for use in the measurement of a combustible component. The flame ionization detector is, however, large and expensive, though it is accurate. As it uses hydrogen gas, it presents a great problem in safety when it is used in a chemical plant, and involves difficulty in portable application. The catalyst type detector is small and inexpensive, but its sensitivity is greatly lowered if the catalyst is poisoned by a certain substance, such as chloride or thionide. It has a relatively short life due to oxidation upon exposure to a high temperature, or deterioration by a hot combustible gas. The semiconductor gas sensor is inexpensive and free from any substantial deterioration when an inert gas such as nitrogen or helium, or air is used as a carrier gas. It is, however, useful for measuring only a limited concentration of a combustible component, and low in accuracy. Thus, the known detectors have various drawbacks which hinder their industrial application.